The Committee on Biological Science of the Social Science Research Council has organized a working group to explore the area of biosocial foundations of parenting and offspring development. Its charge is to improve collaboraton among scientists in different disciplines and to identify promising research opportunities and paradigms for further work in the field. Permanent members and organizers of the working group are Alice S. Rossi, sociologist, James B. Lancaster, primatologist, and Melvin J. Konner, anthropologist. The aim of the project is to bring together what have been very different traditions of research and practice in the biological, social, and medical sciences, bearing on parenting and offspring development, for a collaborative confrontation with the scientific issues involved. The key idea is to bring an evolutionary perspective, together with a cross-species and cross-cultural approach, into direct association with behavioral science theory and research on contemporary human reproduction and child-rearing, and with the medical and clinical fields concerned with the physical and emotional health of both the young and their parents. Three intensive workshops focussing on human pregnancy, birth, and early child development are planned. The first two will be exploratory and empirical, seeking to draw together relevant knowledge from diverse fields; the third and final workshop will aim at a synthesis of what the group has learned and a statement of future research needs. About 35 scientists will be involved in the workshops, and significant publications are expected to result.